We've got a couple of Lexmark lasers at home (MS315 and CS410) which default to double-side printing (via putting the paper through twice). They work fine.

I've got an old huge Lexmark T522 in my office that has a bad problem with jambs when the humidity is low (just about any time from October - March). It doesn't do duplex...

Maybe they have better rubber on the rollers now, or something.

As you say, YMMV. :-)